Neoadjuvant Therapy Before Radical Prostatectomy For Clinical T3/T4 Carcinoma of the Prostate: 5-Year Followup, Phase II Southwest Oncology Group Study 9109

Abstract

Several investigators have examined the role of hormonal therapy before definitive local therapy for locally advanced prostate cancer to improve outcome. We evaluated the resectability rate and clinical response rate to 16 weeks of total androgen blockage therapy for clinically locally prostate cancer before radical prostatectomy, and progression-free survival in this multi-institutional study. Southwest Oncology Group 9109 was a phase II feasibility study designed to treat patients with clinical stage C prostate cancer (T3, T4, N0 and M0). Cases were classified by stage T3 versus T4 and bulky (greater than 4 cm.) versus nonbulky (or less 4 cm.) disease. The neoadjuvant agents used were goserelin and flutamide before radical prostatectomy. A total of 62 patients were accrued to the study and 1 patient was ineligible. There were 2 protocol deviations and these patients refused to undergo prostatectomy after hormonal therapy. Four patients went off protocol treatment because they were not considered surgical candidates. The racial distribution was 72% white, 20% black, 7% Hispanic and 2% Asian. Clinical stage at diagnosis was T3 in 97% and T4 in 3% of cases. Of the patients 39% were diagnosed with bulky disease. Of the 61 eligible patients 55 (90%) underwent a prostatectomy. The 5-year progression-free survival estimate was 70% (24 of 61 cases failed) and the 5-year survival estimate was 90% (11 of 61 deaths). Most of the patients in this trial would have been considered inoperable and referred to radiation oncology. Neoadjuvant hormonal therapy followed by radical prostatectomy is reasonable and appropriate for clinical stage T3 prostate cancer. A progression-free and overall 5-year survival of 70% and 90%, respectively, compares favorably to Radiation Therapy Oncology Group neoadjuvant trial outcomes for this stage of prostate cancer.